Lightning-arrester.



D. T. MAY. LIGHTNING ARRESTER. APPLICATION men IUNE 5. I916,

Patented Oct. 2, 1917.

U ITED stra'rns PATENT OFFICE.

DAVID T. MAY, OF NEW YORK, N. Y.; ASSIGHOR T0 WESTEEN ELECTRIC COMPANY, INCORPORATED; OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

LIGHTNING-ARRESTER.

To'all whom. it may concern:

Be it known that I, DAVID T. MAY, a. citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Li htning-r'lrresters, of which the following 1s a full, clear, concise, and exact description.

This invention relates to lightning arresters, and particularly to arresters of the vacuum type. r

Under some conditions of service, it is desir-able to provide, in connection with light 'ning arresters, means for establishing a condnctin path of low resistance in parallel with t e are, if an arc in'urious to the arrester persists between t e electrodes for for establishing a conducting path of low resistance in parallel with the are, if an injurious are between the electrodes persists longer than a certain period of time, such that the arrester, can easily'bc restored to normal condition withoutextensive disasscmbling. L

' The drawing shows, partly in section and partly diagrammatically, a vacuum lightning arrester having the present invention embodied therein. A

The evacuated container 5, within which the electrodes of the arrester are mounted, may be of lass or other suitable material formed am evacuated in the same wellknown manner as are incandescent lamp bulbs, the pointfi indicating the place at which the bulb is sealed after the evacuation. Within the container 5 is an electrode sup port comprising a hollow stem 7 resembling the well-known form. of stem used in incan-' descent lamps, said stem having a flared bot tom 8, the edges of iwhich are welded at 9 to the edges of the chntaincr 5. The hollow stem 7 projects well up into the container 5 Specifica tiiiii of Letters 2mm.

.19 and themanner in which Patented Oct. 2, 1917.

Application filed June 5, 1916. Serial No. 101,747:

and serves as a support for the electrodes of the arrester. As shown in the drawing, the stem 7 carries an inner cylindrical electrode 14, whiclrmay be of sheet metal having the threaded form shown and having a series of groovy-d leaves 13, which enga e with a boss ormed in the stem 7 and hol the electrode 14 in place. The outer' elcctrode15 is alsocylindrical and may be of sheet metal having the thrcadedj form shown in the drawingand may be surrounded by asheet metal shell 16, as shown; The outer eleetr'ode 15 is held in proper relation to'the inner electrode 14 by washers'lS and 19 of insulating material, which may be perforated, as shown at 20, in order to permit the ready evacuation of the space between the electrodes and to afford vents for the relief of any pressure created in said space by an are between the electrodes. The orm of the washers 18 and they coiiperate with the electrodes 14 and 15 are apparent from .the drawing, from which it is evident that the electrode structure can be easily as- The necessai airtight seal may be obtained in the wellnown manner by inter )osing pieces of platinum 25 in saidleai ing-in wires within the glass seal. The inner ends of the leading-in wires 27 and 28 are connected to the electrodes 14- 'andlfi in any suitable manner, as by welding or soldering, or by the-screws 30,115 shown. The outer ends of said leading-in wires are connected 9 to any suitable form of'base which may be cemented to the outside of the container 5. The base shown. in the drawing resembles an incandescent lamp base of well-known form, but instead of being threaded on its outer surface, is provided with projections 31 which are adapted to eoiiperate with slots or grooves in a supporting socket so as to provide a socalled bayonet connection; lhe projections 31 may be riveted or othcrwise suitably attached to the shell 32, which may be of brass or other suitable material. At its bottom, the shell. is span in, as shown at 3; and is embedded in molded insulated material 34, in which is also embedded a brass sleeve 35, hereinafter more fully described. In manufacture, the base consisting of the shell 32, the molded material 34 andthe sleeve 35 is cemented to the end of the container 5, to which has been welded the hollow stem 7, su porting the electrodes. Before attaching t e base, the leading-in wire 27 should be-soldercd to the sleeve 35, as is shown at 36. The other leading-in wire 28 is brou ht out between the container 5 and the she I 32, and is solderei to the edge .of the shell, as shown at 8 The means for establishing a conducting path of low resistance in parallel to the arc, if an injurious arc persists for longer than a certain period of time, will now be described: This means is located entirely outside of the evacuated container 5, and is arranged to; be readily renewable As shown, it comprises a tube 40 having -a threaded end adapted to screw into the sleeve 35, and a rod 41, which extends through the tube 40 and is soldered thereto at 42 near the inner end thereof. The rod 41 projects from the base of the lightning arrester, and is adapted to engage a spring contact member 44 and to hold it away from the contact member 45 with which the spring contact 44 tends to engage. A circuit in which the lightning arrester might be used is indicated in the drawing, which shows the contact spring 44 connected to the line L to be protected, and the contact member 45 and shell 32 of the arrester permanently connected to ground.

The tube 40 and rod 41 are of such a length that the inner ends thereof are lo cated inside of the hollow stem 7 at a point where the solder 42 will receive heat from an are between the electrodes 14 and 15. The melting point of the solder 42 should be such that the heat received b it from an injurious are which ersists etween the electrodes for ldnger t an a certain period of time, is sufiicient to melt the solder. The proper solder can easily be determined by ex criment. When the solder 42 melts, the re 41 is moved upward by thespring 44, which moves into engagement with the contact 45, thereby electrically shunting the electrodes 14 and 15 and completing a circuit from the line L directly to ground. After the shunting device has operated, it is a simple matter to restore the lightnin arrester to its normal condition, because a 1 that is necessary is to remove the arrester from its supporting socket, and then to remove the tube 40 and rod 41 and to either resolder them or replace them by a new tube and rod properly soldered together, after which the arrester may be restored to its socket.

While the present invention is shown embodied in a vacuum lifihtning arrester of a particular kind, it wi be understood that it is adapted for use in connection with vacuum arresters of many difierent types.

What is claimed is:

1. In a vacuum lightni-n arrester, an evacuated container, electro es therein, a hollow stem projecting into said container, and means in said stem and actuated by the heat of the are between said electrodes for electrically shunting said electrodes if an injurious arc persists between them longer than a certain period of time.

2. In a vacuum lightning an'ester, an evacuated container, a hollow stem project- 'ing into said container, electrodes supported thereby, and means projecting into said stem and actuated by the heat of the arc between said electrodes for electrically shuntingbsaid electrodes if an injurious arc persists etween them longer than a certain period of time.

3. In a -vacuum lightning arrester, an evacuated container, a hollow stem projecting into said container, hollow electrodes supported thereby, a. tube within. said stem, a rod extending into said tube, fusible means securing said rod to said tube at a point within said electrodes, and contact means controlled by said rod for short-circuiting said electrodesii an injurious arc persists between them longer than a certain period of time. i

In witness hereof, Iv hereunto subscribe my name this 3rd day of 'June AT. D., 1916. DAVID T. MAY. 

